1. Field of the Invention
The present invention relates to a leaf spring engaged with a pair of spaced support members at opposite ends thereof in a compressed condition to effect outward biasing forces in a longitudinal direction thereof and a mounting construction of the leaf spring, for example, in a keyboard apparatus of a musical instrument.
2. Description of the Prior Art
Illustrated in FIG. 7 is a conventional leaf spring 1 which is engaged with a pair of spaced support members 2 and 3 at opposite ends thereof in a compressed condition to effect outward biasing forces in a longitudinal direction thereof. In this mounting construction, the leaf spring is deformed in a C-letter configuration so that the opposite ends of the leaf spring are formed as nodes N1 and N2 while an intermediate portion of the leaf spring is formed as an antinode. In U.S. Pat. No. 4,901,614 issued on Feb. 20, 1990, there is disclosed a leaf spring of this kind assembled within a keyboard apparatus to bias a key and swing lever toward a frame structure.
In the case that a rolled steel plate is used to provide the leaf spring 1 by press forming, the leaf spring 1 warps in a free condition. If the leaf spring in the free condition warps in a pressed direction, the outward biasing forces P1 and P2 acting on the support members are decreased in accordance with the warp of the leaf spring. If the leaf spring in the free condition warps in the opposite direction, the outward biasing forces P1 and P2 acting on the support members 2 and 3 are increased in accordance with the warp of the leaf spring.